Composite metal layers for fabricating deep drawn articles



. E. A. MILLER v COMPOSITE METAL LAYERS FOR 'FABRICATING 1 DEEP DRAWN ARTICLES Filed Feb. 1967 Jan. 20, 1970 In mentor, EdwinA.MiZZen United States Patent O US. Cl. 29-191 7 Claims ABSTRACT OF THE DISCLOSURE Layers of metallic materials of selected earing properties are bonded together to form a composite material, theearing properties of the different material layers being arranged to complement or counteract each other so that the composite material has improved earing properties for use in fabricating deep drawn articles.

BACKGROUND OF THE INVENTION When metallic strip materials are cut into round blanks and deep drawn for making cup-shaped articles or the like, the rims of the cups, instead of being straight or level, tend to be undulating with a series of high points called ears and low points called troughs. The presence of these ears is undesirable, particularly if the ears are of a significant height, and such cups usually must be machined after drawing for removal of the ears.

The earing of metallic materials during deep-drawing is attributed to a particular orientation of the crystals within the original strip material. This orientation arises from the deformation and annealing processes used in production of the strip material and causes the crystals to further orient in a preferential manner during subsequent deep-drawing of the material. Various earing properties are observed in commercially available metallic strip materials but, generally speaking, the materials tend to form ears at least four at locations around the rim of a cup, these locations being disposed either at angles of 45 to the direction in which the strip material was primarily deformed during production of the strip or at angles of and 90 to said direction of deformation. For example, in the case of some aluminum alloys, strip materials in which textures are primarily determined by rolling tend to display 45 earing properties whereas more fully annealed strips tend to display 90 earing properties. On the other hand, different metals and alloys tend to display different earing properties.

When single layer materials are used in making deepdrawn articles, the earing effect resulting from inherent material properties can be minimized or even eliminated by proper control of the drawing deformation in a series of steps and by intermittent annealing of the blank material between the drawing steps. However, when composite materials formed of several material layers are subjected to a deep-drawing process, the deformation and annealing steps useful in minimizing earing for one of the material layers will frequently not be effective in minimizing earing in another material layer. Further, particularly where one layer of a composite material is relatively thin or has a relatively low melting point or the like, the composite material frequently cannot be subjected to temperatures appropriate for minimizing earing without damaging the composite material or the bonds between various layers of the composite material. In this regard, note that temperatures employed for counteracting earing tendencies of materials are usually considerably higher than the minimum temperatures required for recrystallizing the materials.

3,490,124 Patented Jan. 20, 1970 ice SUMMARY OF THE INVENTION In accordance with this invention, a composite material for use in fabricating deep-drawn articles is formed by bonding strips or layers of metallic material together with the material layers oriented with respect to each other so that the earing tendencies of the separate material layers counteract each other in the composite material, thereby providing the composite material with excellent earing properties. For example, one metallic strip material which tends to form ears at angles of 45 to the direction in which the strip material has been previously deformed is bonded to a second strip material which tends to form ears at angles of 0 and to the direction in which the material has been previously deformed, the strip materials being oriented with respect to each other so that said directions of principal deformation are substantially parallel to each other in the composite material. In this way the bonded composite material is adapted to display excellent earing properties and when subsequently deep drawn for fabricating deep-drawn articles, tends to form eight relatively very small ears around the rims of the articles. These very small ears are insignificant in many such deepdrawn articles so that the articles can frequently be used without requiring removal of the ears or the ears can be easily removed with loss of very little of the article ma terial.

Other objects, advantages and details of this invention appear in the following description of preferred embodiments of the invention, the description referring to the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 of the drawing is a perspective view of apparatus diagrammatically illustrating the method of this invention;

FIGS. 2 and 3 comprise perspective views of a blank conventionally used in forming deep-drawn articles and of an article formed from the blank;

FIGS. 4 and 5 comprise perspective views of another blank conventionally used in forming deep-drawn articles and of an article formed from the blank; and

FIGS. 6 and7 comprise perspective views of a blank formed of the composite material of this invention for use in forming a deep-drawn article and of an article formed from the blank.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the drawings, 10 in FIG. 2 illustrates a round blank cut from a strip of malleable metallic ma terial in conventional manner for use in forming a cupshaped article by conventional methods of deep drawing. The direction in which the blank material has been primarily deformed during original manufacture of the material is indicated at 12 in FIG. 2. The blank is formed of copper, aluminum, steel or other malleable metal or metal alloy and has 0 and 90 earing properties such that the blank tends to form ears at locations indicated at 14 disposed at angles of 0 and 90 to the direction of original material deformation 12. That is, when the blank is subsequently deep-drawn by conventional techniques to form the cup-shaped article 16 illustrated in FIG. 3, the inherent earing properties of the blank material tend to form ears 18 at locations around the rim of the cup disposed at angles of substantially 0 and 90 to the primary direction of deformation 12 of the original blank material.

In FIG. 4 there is illustrated another deep-drawing blank 20 of a material such as copper, aluminum, steel or other malleable metal or metal alloy having 45 earing characteristics. The direction in which the material of the blank 20 has ben primarily deformed during original manufacture of the blank material is indicated at 22 and the locations at which the blank material tends to form four ears during subsequent deep-drawing are indicated at 24 in FIG. 4. That is, when the blank is subsequently deep-drawn by conventional techniques to form the cup-shaped article 26 shown in FIG. 5, the inherent caring properties of the blank material tend to form four ears 28 at locations around the rim of the cup disposed at angles of substantially 45 to the primary direction of deformation 22 of the original blank material.

Referring now to FIG. 1 of the drawings, 30, 32 and 34 indicate strips or sheets of malleable metallic materials of substantial length coiled in reels 36, 38 and 40, which materials have been primarily deformed during production thereof in directions extending longitudinally or lengthwise of the strips as indicated at 42, 44 and 46 respectively. The strip 30, for example, preferably comprises an aluminum alloy commercially available under the designation 1100 or 25 of a thickness of .090 inch and a width of 1 inch. Such material, when annealed at 550 F. for 2 hours after 70% reduction during manufacture, is known to display pronounced and 90 earing properties similar to those described with reference to the blank in FIG. 2. The strip 32 preferably comprises another aluminum alloy available under the designation 3003 or 35 of the same width and thickness as the strip 30. This latter alloy, when similarly processed during manufacture, is known to display 45 caring properties such as those described with reference to the blank in FIG. 4. The strip 34, for example, preferably comprises a relatively much thinner strip of copper of .010 inch thickness and of a width of 1 inch. The caring tendencies of this copper strip will be substantially disregarded herein in view of the significantly smaller thickness of the copper material as will be understood.

In accordance with this invention, the surfaces of the strips 30, 32 and 34 are preferably cleaned and substantially freed of barrier films and are then advanced in layer relation between the rolls 48 of a conventional roll squeezing means such as are diagrammatically illustrated in FIG. 1. That is, the strip materials are advanced from the reels and are brought into interfacial contact progressively from end to end of the strips as they are fed from the reels. In order to properly clean the strip surfaces, the strip surfaces are preferably subjected to wire brushing or the like in a surface preparation apparatus indicated at 50 such as is described in US. Patent No. 2,691,815 of H. Boessenkool et al.

As the methods for cleaning the strip surfaces are conventional, they are not further described herein but it will be understood that the strip surfaces are prepared in any conventional manner to be subsequently bonded together.

As the strip materials 30, 32 and 34 are brought into interfacial contact and are advanced between the rolls 48 of a conventional strip metal rolling mill, the strip materials are substantially reduced in thickness by deformation of the materials in the direction indicated by the arrow 54 in FIG. 1 for solid-phase metallurgically bonding the strip materials together to form the composite strip material 56. Where the specific strip materials are used as above described, the rolling is preferably accomplished without the addition of heat from any outside source and with approximately 70% reduction of the strip thicknesses. It Will be noted that, in the described process, the principal directions of deformation 42, 44, and 46 of the original strip materials are parallel as the strips are advanced toward the rolls 48 and that the strips are further deformed in a parallel direction 54 between the rolls 48. Preferably the composite strip material is then sintered in the manner described in the patents noted above for improving the bonds between the strip materials. It should be understood that although a process for solid phase bonding of the strip materials has been described by way of illustration, the strip materials could be bonded together by hot rolling, liquid phase bonding or in any o her conventional manner Within the scope of this invention.

The composite strip material 56 formed in the mapner above described has improved earing properties and is especially adapted for fabricating cup-shaped articles and the like by the use of conventional deep-drawing techniques. For example, where a round blank 58 shown in FIG. 6 is cut from the composite strip material 56 by conventional punching techniques or the like, the layers 30, 32 and 34 of the composite material each contribute to the eating properties of the composite material and tend to form cars at different locations during deep-drawing of the composite material. That is, as is indicated in FIG. 6, the layer material 30 in the composite material 56 tends to form four ears during subsequent deep-drawing of the blank 58 at locations indicated at 60 in FIG. 6. The layer material 32 however tends to form four ears during subsequent deep-drawing of the blank at locations indicated at 62 in FIG. 6. Note that the directions of material deformation are indicated at 42, 44 and 54 on the blank 58. The layer material 34 also tends to form ears during subsequent deep-drawing of the blank but, in view of the relatively thin character of the strip 34, the earing contribution of the strip 34 is disregarded in this illustration as noted above.

As will be understood, when the blank 58 is subsequently deepdrawn by conventional techniques to form the cup-shaped article 64 shown in FIG. 7, the blank material tends to form eight relatively very small ears 66 at locations equally spaced around the rim of the cup '64, these ears being disposed at angles of 0, 45 and to the direction of deformation as indicated in FIG. 7. Although the ears 66 are shown to be somewhat pronounced for clarity of illustration, it will be appreciated that, when the proper strip materials have been selected and are of substantially equal or related thickness, the cars 66 can be of insignificant size or can be substantially eliminated in accordance with this invention. Such small ears can be ignored or disregarded in many applications of cup-shaped articles such as those described or can be easily removed by abrading techniques and the like without significant loss of the cup material.

Although the process of this invention has been described with respect to the formation of a three layer composite material in which one material layer is so thin as to be of little significance in determining the caring properties of the composite material, the process of this invention is useful in forming composite materials of any plurality of layers by proper selection and orientation of the caring properties of the material layers relative to each other. In this regard, note that where the layer materials employed tend to form ears of approximately equal height, material layers of approximately equal thickness are preferably employed so that the caring properties of the layers fully counteract each other. Where the layer materials do not tend to form ears of about the same height, the thicknesses of the material layers are preferably selected so that the earing properties of the layers counteract each other.

In particular, Where a two-layer composite material is to be formed with one thin layer of one material and one relatively much thicker layer of a second material, the thicker layer is preferably formed of two strip materials in accordance with this invention. That is, the thicker layer of the second material is preferably formed of two strips of material of substantially the same metal or alloy which differ primarily with respect to the caring characteristics of the metal or alloy. That is, in forming a composite material embodying a thin layer of copper bonded upon a relatively much thicker layer of aluminum, the aluminum layer is preferably formed of two aluminum materials in the manner described with reference to FIGS. 1-7 above.

Although particular embodiments of the process and material of this invention have been described by Way of illustrating this invention includes all modifications and equivalents thereof which fall within the scope of the appended claims.

I claim:

1. A composite metal material for use in fabricating deep-drawn articles comprising a plurality of metal layers metallurgically bonded together, at least two of said metal layers embodying materials having preferred grain orientations therein sufficient to provide said layer materials with significant earing properties, at least two of said metal layers with said preferred grain orientations being disposed relative to each other within said composite material with one layers preferred grain orientation Within said composite material differing from the other layers preferred grain orientation within said composite material, whereby the earing properties of at least two of said metal layer materials with said preferred grain orientations will tend to counteract each other during deep-drawing of said composite material to minimize earing of said composite material.

2. A composite material as set forth in claim 1 wherein at least one of said layer materials has a preferred grain orientation therein providing said layer material with substantially 45 earing properties and at least one other of said layer materials has a preferred grain orientation therein providing said other material with substantially 0 and 90 earing properties, said layers being disposed relative to each other within said composite material with one of said layers preferred grain orientation within said composite material differing from the other layers preferred grain orientation within said composite material, whereby the earing properties of said layers with said 45 and with said 0 and 90 earing properties will tend to form ears at different locations during subsequent deep-drawing of said composite material.

3. A composite material for use in fabricating deepdrawn articles comprising at least two layers of metallic material .metallurgically bonded together, at least a first layer material having been primarily deformed in a selected direction during manufacture thereof and having a preferred grain orientation therein providing said layer material with a tendency to form at least four ears at cations disposed at angles of substantially 45 to said direction of material deformation during subsequent deepdrawing of said layer material, and at least a second layer material having been primarily deformed in a selected direction during manufacture thereof and having a preferred grain orientation therein providing said layer material with a tendency to form at least four ears at locations disposed at angles of substantially 0 and to said direction of material deformation during subsequent deep-drawing thereof, said first and second material layers being oriented relative to each other Within said composite material with said directions of deformation substantially parallel.

4. A composite material as set forth in claim 3 embodying two material layers wherein said preferred grain orien tations provide said layers materials with the tendency to form ears of substantially the same extent.

5. A composite material as set forth in claim 3 embodying at least three material layers wherein said first and second material layers having said preferred grain orientations have substantially greater thickness than other layers of said composite material.

6. A composite material as set forth in claim 5 embodying only three material layers wherein said first and second layers having said preferred grain orientations embody substantially the same materials differing primarily with respect to the orientation of said earing properties with respect to said respective directions of material deformation.

7. A composite material as set forth in claim 6 wherein said first and second layers embody aluminum materials and said other layer embodies copper material.

References Cited UNITED STATES PATENTS 1,845,155 2/1952 Jordan.

1,997,166 4/1955 Brown 2919'7.5 2,383,511 8/1945 Reynolds 29-1975 2,713,196 7/1955 Brown 29196.1 X 2,735,170 2/1956 Moffatt.

2,947,069 8/ 1960 Carlson 29-197 3,042,428 7/1962 Gardiner 29197 X 3,168,381 2/1965 Finnegan 29-1975 HYLAND BIZOT, Primary Examiner U.S. Cl. X.R. 29194, 197.5 

